These studies are proposed to define the early response in bound and free calcium during activation of human monocytes and during the initiation of T and B lymphocytes into the mitotic cell cycle. A computerized, mathematical analysis has been developed to analyze 45Ca uptake into resting and stimulated lymphocytes and monocytes so as to define the exchange time constants and pool sizes of calcium within the cell. These measurements will be correlated with the total cell calcium content and the cytoplasmic concentration. These studies should define how calcium is transported, distributed and regulated in the early moments leading to monocyte activation and to Tand B-lymphocyte proliferation. We propose further to study the relationship of the early responses in calcium metabolism to the activation of monocytes as judged by superoxide production and to the stimulation of T and B lymphocytes as judged by increases in protein, DNA and DNA synthesis. The internal stores of calcium will be depleted to assess the effect of diminished calcium stores on the cytoplasmic free calcium response to stimulation. This investigation will determine whether an increment in free calcium is necessary and/or sufficient to mediate superoxide production in monocytes and synthetic processes in lymphocytes. Further experiments with phorbol myristate acetate and diacylglycerol which cause little increase in free calcium, will clarify the role of the baseline calcium level in cell activation since both stimulate protein kinase-C which is sensitive to the resting free calcium. Studies are proposed to define the membrane and cellular mechanisms of calcium metabolism in neoplastic chronic lymphocytic leukemia (CLL) B lymphocytes, and to compare them with normal T and B lymphocytes to establish whether an abnormality exists in CLL cells when stimulated to enter the cell cycle. (A)